The currently used device in most logging operations involves a solid metallic ball having two apertures at right angles extending completely through the ball and intersecting each other at the center of the ball. The cable is inserted through one of the apertures and the ball is moved longitudinally along until it is located at the desirable spot. Then a spike is driven through the cable and through the other aperture in the ball, the spike extending perpendicular to the aperture in which the cable has been threaded. The obvious disadvantage is that driving the spike through the cable tends to weaken the cable structure at that point. There may be other companies in the business of making such devices, but the one known is the Christy Company.
An alternative embodiment is a pair of semi-spherical elements bolted together over a cable.
The functional equivalent of the Christy ball is a knot tied in a rope illustrated in U.S. Pat. No. 504,522 to Donahue. But tying a knot in a one inch steel cable is not only physically impractical, but is also a structure which would tend to weaken the cable itself.
U.S. Pat. No. 4,351,257 to Brown involves a fender used in marine applications but also discloses a way of locking an attachment to a cable.
U.S. Pat. No. 4,367,982 to Hubbard discloses attaching a stopping mechanism to a cable involved in marine applications by the method of a pressure screw threaded perpendicular to the cable and into frictional engagement therewith. It is obvious that the transverse compression of the cable would tend to weaken it, particularly because of the limited bearing area of the pressure pin on the cable.